ShareArticleOctober,2008

AW5550/AF2333:DiagnosisandValveBodyInformation

BobWarnke

Adapting to the Aisin Warner 5550SN Valve Body

Some things are less intimidating, if your not the first one to do it. That statement is relative toboth the crossing of a frozen lake and a problematic 5550SN. Because of a heavy snow cover, itcannot be assumed the ice is sufficient for support. What you cannot see may result in a sink orswim experience. On the 5550SN valve body, a clean core is not indicative of the function.

This material is a route past the thin ice that other travelers have marked. At these flags persay, the test or inspection, frequently points to the valve body, as it accounts for the majority ofthe transmissions issues. The 5550/51SN is installed into a multitude of vehicles and therewill be variations to the unit and this data. A similar valve body will bolt to a GM, Volvo,Saturn, Nissan, Saab, Opel or Renault. Failure to test and recognize can create hours ofadditional effort.

Pressure and Fill:

All the pressure plugs have a 12mm head. Do not mistake the 27mm band anchor (see Figures1 and 2) for a fill plug or pressure tap. If that anchor is removed, the band will have to berecaptured. Positioning the band requires removal of the servo, at best and possibly thecomplete transmission.

The turbine sensor hole can be use to improve the fill speed. Low fluid or excessive overfill, cancreate erratic pressure and poor linear solenoid control, eventually forcing a TCM highpressure strategy.

If the transmission is in the vehicle, test the ice per say, at the pressure taps relative tothese complaints:

TCC RPM Fluctuation and Overheated Fluid

Check lube pressure. The lube pressure tap is between the secondary regulator valve and themain shaft bushings. Lube pressure will be affected by the fluid viscosity (flow rate) and thebushing to shaft clearance. Sufficient pressure at operating temperature indicates the filter,pump and both primary and secondary regulators are functioning. Normal lube pressure at theport indicated 10 f. lube pressure can be as high as 30 psi. At 150 f, normal lube will be 5 psi.in Drive and 8 psi. in Reverse. This indicates the bushings are in place and can retain some ofthe source pressure. Lube pressure that starts low and stays at zero psi, would indicate yourpump output is low, the regulator valve bore is worn or your bushings are bad.

If you are diagnosing a TCC complaint perform a cooler flow test. Normal flow in Drive withTCC released is 1.3 gpm and during TCC apply it drops to .7 gpm. The Saab, cooler elementwill require an adapter, but most units are easily accessible.

Lube pressure and flow on the 5550SN, is low in comparison to other units. This converterrequires multiple valves, along with the rear pump bushing, to control modulated TCC apply(see Figure 3). The converter clutch may remain fully applied at very low speed and high load,which taxes the fluid and lining, creating a breakaway slip or RPM fluctuation.

Delayed Engagement and Poor/Flare Shifts

Check SLT pressure and C1 clutch. The C1 clutch is engaged via pressure rise by SLT solenoidand through a series of modulated valves. The SLT pressure should start at 5 psi. in Drive andincrease with throttle and load to 80 psi maximum. SLT will cutback and spike on variousshifts, depending on the TCM program.

Typical C1 pressure is 0 in Park. As Drive is selected, it quickly steps to 25 psi., then 50 psi,within half second and remains, until accelerated. C1 psi. will then follow load, with amaximum near 200 psi. If C1 pressure upon selecting Drive is immediately 160 psi. andobtains 200 psi. during a shift, the unit may be under a TCM code/ failsafe mode. Engagementsat this time are abrupt. Some vehicles ( Volvo specifically) may use a C1 disengagement viabrake signal creating a neutral at idle. Check for a TCM flash to eliminate this condition.

23 shift Flare, Neutral or Harsh

Compare the B4, servo apply pressure, to the C1 clutch. The B4 tap is at the top of the case, inline with the linkage bolts.The B4 circuit has extensive valve body control and includes a tube with oring ends that feedthe servo. Comparing C1 to B4 is an indication of control by the SLS and SLT linear solenoids,a failsafe or leakage condition.

Proper B4 pressure should follow C1 and never be less than 10 psi.of C1. (Refer to the C1pressure testing.) If C1 psi. is fixed at 160 psi. upon engagement, the 12 and 34 shift, may beacceptable, but the 23 is generally too harsh. A TCM pressure management, code, aerated fluidor bad speed sensor, will eliminate the SLT pressure curve and force B4 to an immediate 200psi. which results in the harsh 23 shift. If the pressure curve of both C1 and B4 are parallel, C1 initial engagement is near 50 psi. and the 23 harsh, the vehicle may require a flash update,but perform a key cycle and numerous drive cycles first. Some manufactures ( Volvo) haveservos and a reflash to improve 23, 32 driveability.

SLT Air Test:

Before removal of a valve body, from the transmission, you can perform a visual wet air test ofthe SLT circuit.

If you pressurize the SLT port with shop air ( 80100 psi), air pressure will push fluid, whichyou see as a leak. Problematic leaks occur at the steel side cover, SLT accumulator, B1 and C1control valves. A major leak or combinations, cause delayed engagement or flare upshift andshould be inspected after disassembled.

You can perform a similar air test (Figure 4) with the valve body itself. When doing so, thepump line port and thermal element hole must be closed and the separator plate held as shownto eliminate cross leaks. This might sound confusing in print, but when you do it, the ports willbe evident and easy to close with an opposite hand.

Valve Body Inspection:There are many variations, which complicate coring and matching parts. Figure 5 identifiesvisual changes. Currently there are 6 different shift solenoids, 4 of which can be installed inincorrect locations or replaced by a normally open vs. normally closed solenoid. The shiftsolenoids should be checked for proper flow when open and their seal when closed. These arefed line pressure from an orifice in the plate and can be over pressurized.

Three linear solenoids are calibrated to the valve body. Exchanging SLT, SLS solenoids betweencores, without adjusting to the valves, is generally not acceptable. Dont hesitate to open andinspect the valve bodyas its comparable to other Asian Warner designs and not difficult to

reassemble. That inspection should include all the removable sleeves, both regulator valves andthe solenoid modulator bore. The linear solenoids are fed by this modulator valve which limitsthe maximum pressure. When that bore is worn, the concern is similar to a bad GM actuatorfeed circuit.

Excess wear appears as a discoloration, or polished area, in the shape of a moon phase,generally at the ends of the bore or opposite side of fluid entry (see Figure 6).

5550 SN &/or AF23/33

All solenoids are 5.05.6 ohms and operate at 300Hz. Between 10 and 40% duty cycle. Note:Bracket changes on Linear solenoids. Length of Linear SLTSLS varies.

SLURemains Same EarlyLate

SLTEarlySlot for bracket results in solenoid connectors upwardBracket is narrow type

Distance bracket slot out ex. 1.408 (short manifold)

SLTLateSlot for bracket results in connector downWider bracketLong manifold 1.510Connector down requires special harness, Volvo update

SLSEarlySlot for bracket requires connector upNarrow bracketShort manifold 1.408

SLSLateSlot for bracket requires connector upWide bracketLong manifold 1.510

SLSN.O.Controls clutch feed pressure at shift pressure control valve

SLU N.C.Controls TCC applyB4 servo applyB2 neutral control

Rebuild Comments:

1. G.M. & Saab use different TCM strategy compared to Volvo & Renault.

2. Input & output speed sensors are Hall affect.Be sure to clean them and keep away from stray frequencyHarsh shifts, high line pressure & TCC concerns can be caused by input contamination,also Gear ratios, TCC cycling, 35 shift, phantom codesAdd ground straps & distance the sensors from Linear solenoid wiring

Valve Body Exchange:

G.M. Equinox valve body has been installed successfully onto Volvo. In order to do so, a wiringharness must match SLT Linear connector either positioned up or down.

#2 solenoid is N.O. on G.M. must use Volvo N.C. on #2Always resurface castings on all valve body areas

Seal end plugs for C1 control, B4 release, B1 control

Linear Lockup Solenoid ( SLU)

This Solenoid Affects:12 upshift. ie too firm or bumpy21 downshift. ie harsh, bumpLight throttle TCC modulation. ie cycling rpm or cooler flowFull TCC lockup. Ie late, bump on coast down releaseTCC release on coast too early, loss of engine braking

Refer to the pressure chart for examples of operation.

SLU Service and Adjustment at the Bench:Premeasure the adjuster, remove the threaded adjuster, then the valve from the solenoidVerify the pintle (shaft passing through coil), is free floating by performing a shake testReassemble and turn the adjuster to the original position

Driveability and VBT Test Stand Verification:The SLU is pulsed during 12, 21, 23, 32 shift, also during engagement into Drive orReverse and TCC apply. Monitoring cooler flow with a SonnaFlow will indicate if theSLU is adjusted properly. A quick flow reduction of 50% and then a return, indicates theSLU is reacting to TCC valves. For example, 1.0 gpm. in Park, then upon Driveengagement, a sharp drop to .06, and a quick return, identifies the correct actionIf you have harsh up/down shifts and you do not see a cooler flow toggle, the SLU is notadjusted or working properlyThe correct adjustment on SLU will increase cooler flow. Improper adjustment willreduce cooler flow, substantially

SLU Adjustment in the Vehicle:The solenoid can be adjusted if a passthrough hole has been located in the cover duringbench rebuild. The SLU access will be at the top, left corner. A 3 mm Allen wrench, willpass approximately 1.60 or 40.9 mm. through the cover, when its inserted into theadjuster. You should be able to feel the Allen engagement. As you turn the Allen wrenchyou will feel the retainer click over the index. Always count your rotations, in clockwise(CW) or counterclockwise (CCW), so you know where you start/stop

CW/In reduces SLU output resulting in:Hard 12, 21 shifts Firmer/later TCC

CCW/Out increases SLU output resulting in:Softer shifts Earlier TCC

Road Test:If your TCC control, 12 and 21 are good, cooler flow drops properly as noted above,leave the adjustment as is. If not, adjust accordinglySlight bump on 21 downshift and/or TCC rpm fluctuates at 3040 MPH duringmodulated apply.and/or excess TCC slip at full lockupand/or SonnaFlow sensorindicates TCC control valve is continually toggling onoff. If so turn adjuster screwin/clockwise 1.0 turnHarsh 21 downshift.and/or heavy TCC RPM fluctuation at 3040 mphand/or lateand firm full TCC apply. If soturn adjuster in/clockwise 1.5 to 2.0 turnsTCC will apply not modulate slip RPM at 3040 mph. Beyond 40 mph, TCC apply isshort and harsh. and/or a harsh TCC release on coast and/or 12 shift is too harsh.The adjuster is too far inward, back it out/ counter clockwise as required 1.5 to 2.5 turnsLow cooler flow when in lockup. No TCC flow drop upon engagement or shifting.Adjuster may be too far out/CCW

Notes:The spring between the adjuster and the valve tends to have some memory or coil wrapup. If you overcompensate in one direction, it may require more of an opposite directionto restoreDuring road test, you will need a temporary plug in the access holesIf you can feel the adjuster turn out against the retainer, STOP or you can force theretainer off. If you have adjusted to this point, you are beyond resolving a problem witha solenoid adjustment. Generally 12 turns in/ out is all that is needed

Line Pressure Solenoid ( SLT)

This Solenoid Affects:Reverse engagement. ie too firm, or delayForward engagement. ie delay forwardUpshift/downshift quality. ie: harsh upshifts, coast down clunk23 upshift. ie: long flare, or tail bumpSLT pressure tap. Pressure too low, and slow response

Refer to the pressure chart for examples.

Solenoid Service and Adjustment at the Bench:The service procedure is the same as the SLU and SLS. Measure before and return theadjustment after cleaning

Driveability and VBT Test Stand Verification:The SLT is the line rise control solenoid. It sets the position of the C1 clutch control forforward engagement. It positions the B1 valve for second clutch feed on 12, 21 shifts. Itboosts secondary regulator valve, converter and lube pressure and controls 23 shift atthe B4 control valve. It is a very critical adjustmentEnsure the end plugs at these valves are sealed and secondary regulator bore is not wornor this pressure is either lower, or too high. High SLT and harsh Reverse can be causedby bore wear at the secondary regulator bore, near the spring spoolThis solenoid operates at 300 Hz, and has control between 15 to 45 % duty

Refer to charts and review SLU.

SLT Adjustments in the Vehicle:This access hole is on the right side of the cover, easiest to adjust of all three. You mustmonitor this pressure with a 0100 psi gauge, to set accurately. OE correct SLT, isapproximately 56 psi. in Drive range. Maximum obtained SLT is 78 psi. Turning the SLTscrew inward/clockwise, increases the SLT pressure

High SLT pressure causes (CCW/Out, reduces SLT).Example = 20 psi. of SLT in Drive results in:

Long 23 shift, or an overlap/bind up on 2332 coast down bumpForward engagements become harshTCC apply ramp becomes short and there can be a loss of TCC modulation slip at lowerspeedLube pressure and cooler flow become less at excessive SLT pressure

Low SLT pressure causes (CW/In, increases SLT).Example = 0 SLT in Drive results in:

Causes a Neutral to Drive delay, often with a bang engagementLong shifts and lower than desired cooler flow

Note:Increasing SLT , generally will not eliminate a 23 flare. Check servo design and travel.Then test B4 pressure tap, It should be parallel to C1

Shift Pressure Control Solenoid (SLS)

This Solenoid Affects:Reverse engagementUpshift and downshiftsDoes not affect forward engagementThis solenoid pressure only reacts on the shift pressure control plunger to adjust clutchpressure. It is pulsed to control the feed rate of the clutch dependant on engine load

Refer to the application chart.

The Service Procedure is the Same as the SLU, and SLT Above.

Driveability and VBT Test Stand Verification:The valve body has an SLS access on the backside, with a 10mm hex nut. It is notaccessible in the vehicle. On the VBT the solenoid is operated at 300 Hz. To duplicate thecorrect oncar operation, this solenoid would have the duty % lowered during eachup/down shift. Pressure ranges from 0 to 78 psiEnsure the end plate on the rear control body is flat and the bore of the outer sleeve isnot worn. Generally these do not wear in excess

SLS Adjustments in the Vehicle:The access hole will be located on the left side of the cover, lower than the SLU and inthe bolt radius of the cover. Turning the SLS screw inward/clockwise, increases the SLSpressure

High SLS pressure causes (CCW/Out, reduces SLS pressure):Harsh reverse12 shift harsh23 harsh with an end bumpLoss of TCC applyElevated C1 clutch pressure32 maneuver flare/ bang

Note:Some of the 32 bang complaints are caused by a noncompatible valve body. Some ofthese 32 flare, can be reduced with SLS adjustments

Low SLS pressure causes (CW/In, increases SLS):Soft upshiftsLow speed 23 flareSlight RPM flare on 34, 45 shifts

Note:SLS does not affect forward engagements

High current causes high pressureSolenoid is normally closed (N.C.)300 Hz operating frequency 15%48% duty 1 AMP, TCC is offSLU controls 2nd clutch (B2) and low reverse (B3). Manual low for engine, brakingSLU Has been know to create 12 slip, 21 harsh downshift if not adjusted or defective.It also can overheat fluid and affect TCC applySLU generally controls TCC right after 23, and will maintain TCC apply coasting orcruise at 25 mph.

Chart Example: 03 Volvo V70 XC

300 Hz operating frequency 15%48% dutySLT is normally open solenoid (N.O.)Low current causes higher pressure (inverse proportional)

Chart Example: 03 Volvo XC 70 Vehicle Data

300 Hz operating frequency @ 1540% dutySLS is normally open solenoid (N.O.)

Low current causes higher pressure (inverse proportional)This solenoid is spiked to increase clutch feed, then modulated between shiftsCoast down shifts are modulated also with a pressure rise after each shiftSLS controls: 2nd, 3rd, 4th, B1 brake, 5th, Reverse, C2 clutch

Chart Example: 03 Volvo V70 XC

Note: If C1 pressure upon initial engagement is 160 instead of the 5060 psi, the TCM hascommanded a pressure rise. Verify with SLT amperage, then check for codes and electricalissues.

Separator Plates

Identification:Plates must match the top & middle castingA separator plate modification can be performed, if the secondary regulator bore hasminimal wear. This modification will increase lube and converter feed oil flow.Enlarging the plate feed holes is not suggested if the valve body casting has excessivewear at the secondary regulator bore, in the area of the spring to spool surface

RelatedUnit(s)5550SN5551SN

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